"The Global Positioning System, or GPS, is a set (or 'constellation') of satellites in orbit that people on Earth can use to figure out their exact position on the planet. This may not seem like a big deal if you're close to home where you know all the landmarks -- but what if you're out in the middle of the desert, where one sand dune looks like ... all the others? What if you're in the middle of the ocean, where there aren't a heck of a lot of street signs floating around? Well, if you had a GPS receiver -- small enough to put in your pocket -- you'd be able to send a signal up to the satellites, and they'd send a signal back, telling you exactly where you are. In the GPS Primer, the scientists and engineers who helped develop the GPS constellation at The Aerospace Corporation have given you a short history of the development of GPS, and have described the elements of the systems and how they all work together."

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You may download the Global Positioning System Primer for personal or classroom use. If you wish multiple copies (maximum 50) for educational purposes, please send a letter of request on organizational letterhead to: